Unbreak CI + merge stuff from mailinglist

The GCC was updated and started failing with inconsistent function arguments. Additionally there were couple of patches on mailing list in:

https://archive.libssh.org/libssh/2021-05/0000006.html https://archive.libssh.org/libssh/2021-05/0000007.html https://archive.libssh.org/libssh/2021-05/0000008.html

Checklist

• Commits have Signed-off-by: with name/author being identical to the commit author
• Code modified for feature
• [-] Test suite updated with functionality tests
• [-] Test suite updated with negative tests
• Documentation updated

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTING.md
• This feature/change has adequate documentation added
• No obvious mistakes in the code